Moles make burrows just under the surface of the ground and throw up excavated soil. They live in the burrows and consume insects and other food found in the soil. The burrows tend to kill grass and other vegetation growing above the burrows. The mounds of soil they throw up are unsightly. They multiply and extend their burrows any place where they may find food.
Mole traps have been designed and made over the years to kill moles. These traps have generally had limited success. When making burrow, the moles run into rocks, and man made obstructions. Moles have learned to indentify such objects and burrow around or under them. They avoid detection by the triggering devices on traps frequently thereby avoiding activation of the triggering device and death. Moles apparently avoid activation of traps by not exerting force against metal and other hard objects found in the ground.
Traps that are activated by soil that is pushed upward by moles have some success. Such traps may release spring biased spikes or force moles upward into stationary spikes and death. Moles often avoid releasing the traps by avoiding the application of sufficient force to release a spring or springs. The traps that are available or have been available in the past apply some spring force directly to the spring force release link or links. Moles conserve energy to survive by limiting the force they apply to soil and other materials. The limited force applied by a mole is often insufficient to release the spring force exerted by mole traps on the release linkage or linkages.